Comparison of Intermolecular Interactions of Irreversible and Reversible Inhibitors with Bruton’s Tyrosine Kinase via Molecular Dynamics Simulations

Bruton’s tyrosine kinase (BTK) is a key protein from the TEC family and is involved in B-cell lymphoma occurrence and development. Targeting BTK is therefore an effective strategy for B-cell lymphoma treatment. Since previous studies on BTK have been limited to structure-function analyses of static protein structures, the dynamics of conformational change of BTK upon inhibitor binding remain unclear. Here, molecular dynamics simulations were conducted to investigate the molecular mechanisms of association and dissociation of a reversible (ARQ531) and irreversible (ibrutinib) small-molecule inhibitor to/from BTK. The results indicated that the BTK kinase domain was found to be locked in an inactive state through local conformational changes in the DFG motif, and P-, A-, and gatekeeper loops. The binding of the inhibitors drove the outward rotation of the C-helix, resulting in the upfolded state of Trp395 and the formation of the salt bridge of Glu445-Arg544, which maintained the inactive conformation state. Met477 and Glu475 in the hinge region were found to be the key residues for inhibitor binding. These findings can be used to evaluate the inhibitory activity of the pharmacophore and applied to the design of effective BTK inhibitors. In addition, the drug resistance to the irreversible inhibitor Ibrutinib was mainly from the strong interaction of Cys481, which was evidenced by the mutational experiment, and further confirmed by the measurement of rupture force and rupture times from steered molecular dynamics simulation. Our results provide mechanistic insights into resistance against BTK-targeting drugs and the key interaction sites for the development of high-quality BTK inhibitors. The steered dynamics simulation also offers a means to rapidly assess the binding capacity of newly designed inhibitors

Prognostic Value and Implication for Chemotherapy Treatment of ABCB1 in Epithelial Ovarian Cancer: A Meta-Analysis.

BACKGROUND:Chemotherapy resistance is reported to correlate with up-regulation of anti-tumor agent transporter ABCB1 (p-gp) in epithelial ovarian cancer (EOC), but the results remain controversial. To reconcile the results, a systematic review followed by meta-analysis was performed to assess the association between high ABCB1 status or ABCB1 gene variants and overall survival (OS), progression free survival (PFS), and total response rate (TR) in patients with EOC. MATERIALS AND METHODS:Electronic searches were performed using Pubmed, EMBASE, Web of Science and Chinese Wanfang databases from January 1990 to February 2016. Summary hazard ratio (HR), risk ratio (RR) and 95% confidence intervals (CIs) were combined using fixed or random-effects models as appropriate. RESULTS:Thirty-eight retrospective studies of 8607 cases qualified for meta-analysis were identified. Our results suggested that ABCB1 over-expression was significantly associated with unfavorable OS (HR = 1.54; 95% CI, 1.25-1.90), PFS (HR = 1.49; 95% CI, 1.22-1.82) and TR (RR = 0.63; 95% CI, 0.54-0.75). After adjustment for age, clinical stage, residual disease, histological type and tumor grade, high ABCB1 status remained to be a significant risk factor for adverse OS and PFS. Patients with recurrent ABCB1 positivity suffered from poorer OS than those with primary ABCB1 positivity. However, stratified by chemotherapy regimen, inverse correlation between high ABCB1 status and poor OS, PFS and TR were only found in patients underwent platinum-based chemotherapy but not in patients received standard platinum/paclitaxel-based chemotherapy. No evidence was found for any association between ABCB1 gene polymorphisms and OS, PFS or TR. CONCLUSION:High ABCB1 status is significantly associated with chemo-resistance and poor prognosis in patients with EOC. Large-scale, prospective studies are needed to assess the clinical value of ABCB1 expression in EOC more accurately

MicroRNA-486-5p suppresses inflammatory response by targeting FOXO1 in MSU-treated macrophages

Gouty arthritis (GA) is mainly caused by the precipitation of monosodium urate (MSU) crystals in the joint. Recently, different regulatory roles of microRNAs (miRNAs) in arthritis have been widely verified. Nevertheless, the specific function of microRNA-486-5p (miR-486-5p) in GA is still unclear. GA cell models in vitro were established by the treatment of 250 μg/mL MSU crystals into THP-1 cells or J774A.1 cells. Then, the accumulation of tumor necrosis factor (TNF)-α, interleukin (IL)-8, and IL-β was estimated by ELISA. The mRNA levels of TNF-α, IL-8, and IL-β were measured through RT-qPCR. The protein level of forkhead box protein O1 (FOXO1) was tested via western blot. Furthermore, the interplay of miR-486-5p and FOXO1 was evaluated via the luciferase reporter assay. In this study, MSU treatment successfully stimulated the inflammatory response in macrophage cells. MiR-486-5p downregulation was observed in THP-1 and J774A.1 cells treated with MSU, and its upregulation markedly decreased the concentration and mRNA levels of TNF-α, IL-8, and IL-β. Furthermore, FOXO1 was demonstrated to be negatively modulated by miR-486-5p. The rescue assay indicated that overexpressing FOXO1 reversed the effects of overexpressing miR-486-5p on inflammatory cytokines. Overall, this study proves that miR-486-5p inhibits GA inflammatory response via modulating FOXO1

Environmentally Friendly g-C₃N₄/Sepiolite Fiber for Enhanced Degradation of Dye under Visible Light

Herein, novel visible light active graphitic carbon nitride (g-C3N4)/sepiolite fiber (CN/SS) composites were fabricated via a facile calcination route, exploiting melamine and thiourea as precursors, and sepiolite fiber as support, for efficient degradation of organic dye methylene blue (MB). The as-prepared CN/SS composites were characterized by various characterization techniques based on structural and microstructural analyses. The effects of CN loading amount, catalyst dosage and initial concentration of dye on the removal rate of dye under visible light were systematically studied. The removal rate of MB was as high as 99.5%, 99.6% and 99.6% over the composites when the CN loading amount, catalyst dosage and initial concentration of dye were 20% (mass percent), 0.1 g, and 15 mg/L in 120 min, respectively. The active species scavenging experiments and electron paramagnetic resonance (EPR) measurement indicated that the holes (h+), hydroxyl radical (·OH) and superoxide radicals (·O2−) were the main active species. This study provides for the design of low-cost, environmentally friendly and highly efficient catalysts for the removal of organic dye

Clinical features and underlying mechanisms of KAT6B disease in a Chinese boy

Abstract Background Lysine acetyltransferase 6B (KAT6B) encodes a highly conserved histone acetyltransferase that regulates the expression of multiple genes and is essential for human growth and development. Methods We identified a novel frameshift variant c.3185del (p.leu1062Argfs*52) in a 5‐year‐old Chinese boy and further analyzed KAT6B expression and its interacting complexes and downstream products using real‐time quantitative polymerase chain reaction (qPCR). Furthermore, we assessed its three‐dimensional protein structure and compared the variant with other reported KAT6B variants. Results The deletion changed the leucine at position 1062 into an arginine, resulting in translation termination after base 3340, which may have affected protein stability and protein–protein interactions. KAT6B mRNA expression levels in this case were substantially different from those of the parents and controls in the same age range. There were also significant differences in mRNA expression levels among affected children's parents. RUNX2 and NR5A1, downstream products of the gene, affect the corresponding clinical symptoms. The mRNA expression levels of the two in children were lower than those of their parents and controls in the same age range. Conclusion This deletion in KAT6B may affect protein function and cause corresponding clinical symptoms through interactions with key complexes and downstream products

Histopathological Observation of Aeromonas hydrophila Infection and Influences on Immune-related Enzyme Activity Indexes in Carassius auratus indigentiaus subsp. Nov.

Bacterial sepsis caused by Aeromonas hydrophila infection is one of the most common infectious diseases of Carassius auratus indigentiaus subsp. Nov. It has characteristics of quick onset, high morbidity, and high mortality. Bacterial sepsis has become an important constraint against the industrialization of aquaculture of Carassius auratus indigentiaus subsp. Nov. In this study, Carassius auratus indigentiaus subsp. Nov. were immersed in 1.0×109 CFU/mL Aeromonas hydrophila for infection, the cumulative mortality at 1d, 3d, 5d, 7d and 14d were 10%, 26.67%, 40%, 40% and 40%, respectively. After being challenged with Aeromonas hydrophila, hemorrhage focus and suppuration were observed on the body surface, pelvic fin, anal fin, and tail fin base of Carassius auratus indigentiaus subsp. Nov. Dissecting Carassius auratus indigentiaus subsp. Nov., blackening of the spleen and hemorrhage at the liver were discovered at 3d after being infected with Aeromonas hydrophila. Through tissue section observation, liver tissue was found to have to hemorrhage focus, and vacuolated liver cells, accompanied by inflammatory cell penetration. Inflammatory cell infiltration was also observed in spleen tissues and was most serious at 3d day after infection. After being infected with Aeromonas hydrophila, the gill filaments of Carassius auratus indigentiaus subsp. Nov. were deformed and shortened, gill filament cells fell off, intestinal villi are shortened and mucus cells are increased. After Aeromonas hydrophila infection to Carassius auratus indigentiaus subsp. Nov., the lysozyme content and activities of catalase, alkaline phosphatase, and total superoxide dismutase (T-SOD) in the liver began to increase significantly after the first day and reached a peak on the third day. However, they began to decrease gradually on the fifth day. The acid phosphatase (ACP) activity increased dramatically after the first day, peaked on the fifth day, and then decreased on the seventh day. It is speculated that such changes were attributed to the following two aspects: 1) On the one hand, Aeromonas hydrophila infection stimulates the nonspecific immune system of Carassius auratus indigentiaus subsp. Nov. 2) On the other hand, lesion of tissues occurs after Aeromonas hydrophila infection of Carassius auratus indigentiaus subsp. Nov. reaches a certain extent, thus influencing lysozyme content and the catalase activities, ACP, alkaline phosphatase and T-SOD in the liver

Research progress in molecular biology of fish immunoglobulin D

Immunoglobulins are the primary mediators of the humoral immune response in fish. Studies of immunoglobulins in fish are particularly important for the immunological control of fish diseases. While immunoglobulin D (IgD) was first discovered in 1965, it remains the least understood member of the antibody family. During evolutionary development from fish to humans, IgD has developed critical immunological functions. However, these immunological functions are not well understood. There are two forms of IgD, membrane IgD (mIgD) and secreted IgD (sIgD). sIgD and mIgD are formed by B lymphocytes through different splicing modes. In this paper, IgD's structure and formation process in fish, the distribution characteristics of IgD on B cells, the mediated signaling pathways, and the functions of IgD are reviewed

Characteristics of studies that identify ABCB1 protein (p-gp) expression in epithelial ovarian cancer.

<p>Characteristics of studies that identify ABCB1 protein (p-gp) expression in epithelial ovarian cancer.</p

Forest plots presenting RRs of EOC TR for high ABCB1 expression.

<p>RR = risk ratio; EOC = epithelial ovarian cancer; TR = total response rate.</p